I’m a chemical engineer: I cant find a job due to criminal record after neighbor complained about noise

I had a problem with a neighbour in 2009 that complained about loud music from my house. Although I do not have a hi-fi, our friends sometimes played music when visiting us fropm the car sound systems. To cut a long story short, my neighbour eventually convinced the local detective to take the matter to court. To my amazement I was found guilty but given no fine. While applying for a job at BP South Africa in November 2012, I was informed that I had something on my criminal record. It was then that I found out I had a criminal record. I have since then been struggling to find employment although I have a degree in Chemical Engineering from UCT. I urgently need advice and help on rectifying this mistake on my record and also with possibly suing the Minister of Police. My career and my financial situation are virtually non-existent, and I feel that I may never fully recover from this setback. I can provide more information and documents on request. Yours truthfully Geraldo Geduld